[ELF] - Support moving location counter when MEMORY is used.

We do not expand memory region correctly for following scripts:

.foo.1 : 
 {
   *(.foo.1)
   . += 0x1000;
 } > ram
Patch generalizes expanding of output sections and memory
regions in one place and fixes the issue.

Differential revision: https://reviews.llvm.org/D43999

llvm-svn: 326688